Hint of an exocomet transit in the CHEOPS light curve of HD 172555
Journal article, 2023
HD 172555 is a young (∼20 Myr) A7V star surrounded by a 10 au wide debris disk suspected to be replenished partly by collisions between large planetesimals. Small evaporating transiting bodies, that is exocomets, have also been detected in this system by spectroscopy. After β Pictoris, this is another example of a system possibly witnessing a phase of the heavy bombardment of planetesimals. In such a system, small bodies trace dynamical evolution processes. We aim to constrain their dust content by using transit photometry. We performed a 2-day-long photometric monitoring of HD 172555 with the CHEOPS space telescope in order to detect shallow transits of exocomets with a typical expected duration of a few hours. The large oscillations in the light curve indicate that HD 172555 is a δ Scuti pulsating star. After removing those dominating oscillations, we found a hint of a transient absorption. If fitted with an exocomet transit model, it would correspond to an evaporating body passing near the star at a distance of 6.8±1.4R∗ (or 0.05±0.01 au) with a radius of 2.5 km. These properties are comparable to those of the exocomets already found in this system using spectroscopy, as well as those found in the β Pic system. The nuclei of the Solar System's Jupiter family comets, with radii of 2-6 km, are also comparable in size. This is the first piece of evidence of an exocomet photometric transit detection in the young system of HD 172555.
Stars: variables: δ Scuti
Circumstellar matter
Stars: individual: HD 172555
Comets: general
Techniques: photometric
Author
F. Kiefer
Institut d 'Astrophysique de Paris
Paris Observatory
V. Van Grootel
University of Liège
A. L. des Etangs
Institut d 'Astrophysique de Paris
Gy M. Szabó
Eötvös Loránd University (ELTE)
A. Brandeker
Stockholm University
C. Broeg
University of Bern
A. Collier Cameron
University of St Andrews
A. Deline
University of Geneva
G. Olofsson
Stockholm University
T. G. Wilson
University of St Andrews
S. G. Sousa
University of Porto
D. Gandolfi
University of Turin
G. Hebrard
Observatoire de Haute-Provence
Institut d 'Astrophysique de Paris
Y. Alibert
University of Bern
R. Alonso
Instituto de Astrofísica de Canarias
University of La Laguna
G. Anglada
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
T. Bárczy
Admatis
D. Barrado
Centro de Astrobiologia (CAB)
S. C.C. Barros
University of Porto
W. Baumjohann
Institut fur Weltraumforschung
M. Beck
University of Geneva
T. Beck
University of Bern
W. Benz
University of Bern
N. Billot
University of Geneva
X. Bonfils
Institut de Planétologie et d’Astrophysique de Grenoble (IPAG)
J. Cabrera
German Aerospace Center (DLR)
S. Charnoz
Institut de Physique du Globe de Paris
Szilard Csizmadia
German Aerospace Center (DLR)
M. B. Davies
Lund University
M. Deleuil
Laboratoire d'Astrophysique de Marseille
L. Delrez
University of Liège
O. Demangeon
University of Porto
B.O. Demory
University of Bern
D. Ehrenreich
University of Geneva
Anders Erikson
German Aerospace Center (DLR)
A. Fortier
University of Bern
L. Fossati
Institut fur Weltraumforschung
Malcolm Fridlund
Leiden University
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
Michaël Gillon
University of Liège
M. Gudel
University of Vienna
Kevin Heng
University of Bern
The University of Warwick
S. Hoyer
Laboratoire d'Astrophysique de Marseille
K. Isaak
European Space Research and Technology Centre (ESA ESTEC)
L.L. Kiss
Hungarian Academy of Sciences
Eötvös Loránd University (ELTE)
J. Laskar
Paris Observatory
M. Lendl
University of Geneva
C. Lovis
University of Geneva
D. Magrin
Istituto nazionale di astrofisica (INAF)
P. Maxted
Keele University
M. Munari
Istituto nazionale di astrofisica (INAF)
Valerio Nascimbeni
Istituto nazionale di astrofisica (INAF)
R. Ottensamer
University of Vienna
I. Pagano
Istituto nazionale di astrofisica (INAF)
E. Palle
Instituto de Astrofísica de Canarias
G. Peter
German Aerospace Center (DLR)
D. Piazza
University of Bern
Giampaolo P. Piotto
Istituto nazionale di astrofisica (INAF)
University of Padua
D. Pollacco
The University of Warwick
D. Queloz
Swiss Federal Institute of Technology in Zürich (ETH)
University of Cambridge
Roberto Ragazzoni
University of Padua
Istituto nazionale di astrofisica (INAF)
N. Rando
European Space Research and Technology Centre (ESA ESTEC)
F. Ratti
European Space Research and Technology Centre (ESA ESTEC)
H. Rauer
German Aerospace Center (DLR)
Freie Universität Berlin
Technische Universität Berlin
C. Reimers
University of Vienna
I. Ribas
Institute of Space Studies of Catalonia (IEEC)
Institute of Space Sciences (ICE) - CSIC
N. C. Santos
University of Porto
Gaetano Scandariato
Istituto nazionale di astrofisica (INAF)
D. Segransan
University of Geneva
A.E. Simon
University of Bern
A. M.S. Smith
German Aerospace Center (DLR)
Manfred B. Steller
Institut fur Weltraumforschung
N. Thomas
University of Bern
S. Udry
University of Geneva
I. Walter
German Aerospace Center (DLR)
N. A. Walton
University of Cambridge
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 671 A25Exoplanet diversity with satellite studies
Swedish National Space Board (174/18), 2019-02-04 -- 2023-08-01.
Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Other Physics Topics
DOI
10.1051/0004-6361/202245104